Agricultural research

Historic, Archive Document

Do not assume content reflects current
scientific knowledge, policies, or practices.

Small-
Grain
Pastures

mKk

Page 12

United States
Department of
Agriculture

mmm

April/ 1962

V1

The Morrill Act

April 1962/Volume 10, No. 10

Contents

CROPS AND SOILS

Extra- Attractive Easter Lilies
Boosting Plantain Yields

EQUIPMENT

New Tractor Tire

FOOD AND HOME

Convenient Home Sewing Centers
Distinctive Flavors from Fat

INSECTS AND DISEASES

Insecticides ^
Plant Pests 1/
Bonus from Sterilants
Alligatorweed Control ^

LIVESTOCK

Small-Grain Pastures Pay ^ ,
Parasites Compete or Cooperate \r

AGRISEARCH NOTES

Wilder Medal to ARS Unit ,

Turkey Study Results in Saving {/

Inbred Bent Corn Lines

Earlier Peach Thinning

USDA Siveetpotato Introduction ...

New Pioneering Laboratory K

Woman's Award Winner

Editor: H. G. Hass. Managing Edi-
tor: J. R. Madison. Contributors to
this issue : M. T. York, C. L. Gaddis,
W. E. Carnahan, H. C. Douglass, B.
R. Blankenship, D. W. Goodman, G.
M. Jones, N. E. Roberts, W. W. Mar-
tin, H. F. Lehnert, Jr.

Information in this periodical is public property and
may be reprinted without permission. Mention of
the source will be appreciated but is not required.

The hundredth anniversary of two significant events in the
history of U.S. agriculture are being observed this year.

One is the centennial of USDA, about which we have already
commented on this page. The other is the hundredth anniver-
sary of the Morrill Act, which established the land-grant concept
of higher education.

President Lincoln's signing of the Morrill Act, July 2, 1862,
probably did more to increase college-level educational oppor-
tunities in the U.S. than any event before or since.

The Morrill Act, named for Justin Morrill, a 43-year veteran
of Congress from Vermont, provided that every State should
receive Federal lands on the basis of 30,000 acres for each of
its congressmen. Income from this land was to be used to
endow, support, and maintain "at least one college where the
leading object shall be, without excluding other scientific and
classical studies, to teach agriculture and mechanic arts to
promote the liberal and practical education of the industrial
classes."

By 1870, 47 States had taken steps to establish this new
type of college. Today, there is at least one land-grant insti-
tution in every State, and 20 percent of all college students
in the U.S. attend them.

In addition to offering educational opportunities, the land-
grant colleges and universities have been leaders in bringing
science into the curricula. They have developed scientific
talent that has spilled over from agriculture into every area
of endeavor. Through the land-grant system, large bodies of
scientific facts have been discovered and put to use.

Land-grant institutions also get much of the credit for agri-
culture's ability to produce abundantly and efficiently. Their
contributions aren't limited to our borders. Our efforts to
develop an international understanding of the land-grant system
has been one of America's greatest contributions to world-
wide education.

Many of today's challenges, however, dwarf those of a century
ago. Teaching, research, and extension, as provided by the
land-grant institutions and USDA, continue to provide leader-
ship for the world's agricultural progress.

AGRICULTURAL RESEARCH is published monthly by the Agricultural Research Service, United
States Department of Agriculture, Washington 25, D.C. Printing has been approved by the Bureau
of the Budget, August 15, 1958. Yearly subscription rate is $1 in the U.S. and countries of the
Postal Union, $1.50 in other countries. Single copies are 15 cents each. Subscription orders
should be sent to Superintendent of Documents, Government Printing Office, Washington 25, D.C.

AGRICULTURAL RESEARCH SERVICE
United States Department of Agriculture

2

Laboratory studies confirm theories
about liow insects resist . . .

nsectPd^s

Enzyme changes are involved in the ability
of some insect pests to develop resistance to
the organophosphate family of chemicals

• In laboratory experiments, USDA entomologists have overcome
the resistance of some insects to malathion by combining it with
a synergist — a chemical that restores malathion's toxicity but is
nontoxic itself. Equally important, they know why this chemical
combination proved effective.

Specifically, F. W. Plapp and G. W. Eddy of Corvallis, Oreg.,
killed malathion-resistant houseflies and mosquitoes by treating
them with malathion combined with certain other phosphorous
compounds.

Results of this research confirm theories the scientists based
on previous studies — some by them and some by other scientists.
Previous research had shown:

• Malathion (and other organophosphate insecticides) is toxic
to susceptible insects, because it inhibits the activity of a vital
enzyme, ali-esterase.

• Resistant insects detoxify organophosphorus insecticides more
rapidly than susceptible insects. There is less ali-esterase in the
resistant insects. This ali-esterase is changed to a new enzyme,
enabling the detoxification.

On the basis of this knowledge, selective materials were tested
in combination with malathion in an effort to block the physiologi-
cal mechanism that gives insects resistance.

The chemicals Plapp and Eddy used were tri-substituted aro-
matic and aliphatic derivatives of phosphoric acid. The materials
produced the hoped for synergistic action in the insects by inhibit-
ing the ali-esterase enzyme. Three of the most effective synergists
used were triphenyl phosphate, tributyl phosphorotrithioate, and
tributyl phosphorotrithioite — compounds in the same chemical
family as malathion, but which alone are not effective insecticides.

For their studies the scientists used adult female houseflies and
mosquito larvae. Malathion-resistant and susceptible colonies of
each species were used.

Turn Page

INSECTICIDES

(Continued)

Groups of 20 adult female flies were
exposed to films of the insecticide with
or without synergist in 1-pint glass
jars. Mosquito larvae were tested
by placing groups of 20 in 250 mili-
liters of water in glass jars containing
toxicants.

In all tests, mortality determina-
tions were made 24 hours after initial
exposure to the toxicant.

The synergists either greatly re-
duced or completely overcame resist-
ance. None of them significantly
increased toxicity of malathion to
susceptible insects.

Still not fully understood is the
exact process by which the synergists
work. Plapp and Eddy say the most
logical explanation is that the syner-
gists inhibit the ability of the insects
to degrade malathion by cleavage
of the carboethoxy ester linkages.
Both houseflies and mosquitoes are
known to degrade malathion partially
through hydrolysis at these bonds.
And with one species of mosquito,
Culex tarsalis, increased ability to
degrade by hydrolysis of the carbo-
ethoxy ester is known to be a factor
in resistance to malathion.

On the basis of preliminary results,
the entomologists hope their findings
will lead to a better understanding of
the mode of action of insecticides
and the factors involved in the de-
velopment of resistance in insects. A
better understanding of these basic
questions may lead to more effective
materials or combinations of them
for controlling resistant as well as
nonresistant insects.

The ARS scientists are still con-
cerned with research on the basic
mechanisms involved and with a
search for more promising materials.
Further investigations will be required
to determine the potentialities of these
materials in insect control.^-

Tourists'
baggage, a
favorite
hideaway for
hitch-hiking
agricultural
pests, gets
quarantine
inspection.

Fourth in a Centennial Series

Efforts to keep most destructive insects
and diseases out of the U.S. have been
successful, even though travel and
transportation are increasing

■ The Mayflower probably carried many more insects
than humans. And so did other ships carrying early
American settlers.

These people brought with them such parasitic insects
as lice, fleas, and bed bugs — fabric pests such as clothes
moths and carpet beetles — and houseflies, ants, and
cockroaches.

That was only the beginning of North America's in-
vasion by insect pests and plant diseases. This invasion
continued, and through the 1800's until 1912 the U.S.

4

Inspectors in 1928 board
Graf Zeppelin to look for
farm pests during early
days of air travel.

Fumigation of stored
grain under cover
is ridding U.S. of
khapra beetle, a
tiny, hard-to-kill
foreign grain pest.

From 1900 to 1930,
hopper dozers
cmight many a
g ra ssh o p per — a n d
missed many — on
Western ranges.

Now insecticide frojn
airplane treats
1,000 acres an hour.

was a dumping ground for refuse nursery stock. At least
half this country's destructive insects had entered from
other countries by the time the Plant Quarantine Act of
1912 was passed.

Since passage of this act and the development of port-
of-entry plant-quarantine inspection, the flow of foreign
pests has been stemmed despite ever-increasing interna-
tional transportation and travel. Some pests still gain
entry, but thousands are kept out.

Today, plant quarantine inspectors intercept a plant
pest every 20 minutes. Pests can enter not only via
seaports and borders, but also through the new St.
Lawrence Seaway and the Great Lakes, which reach into
the richest of American farmlands. By jet and other air-
craft, nonstop from Europe, from Asia, and across the
polar icecap, insects travel in air-conditioned comfort
toward the L .S. A particular danger is that insects can
be carried in the luggage of world travelers.

If a pest gets by the quarantine inspectors, additional
kinds of protection are used: early detection; surveys
to pinpoint areas where a pest is established; quarantines
to prevent spread: control to preclude damage; and. when
possible, eradication.

Organized efforts to control plant pests were made
before quarantine legislation was passed. In 1877,
Congress appointed a commission to study grasshopper

and other serious insect infestations, and by 1893. the
first insect-pest survey was undertaken. In 1918. toxic
dust was dumped over the side of an airplane to kill pink
bollworms. This was the first use of aircraft in a pest-
control effort.

Several plant pests have been eradicated from the U.S.
These include parlatoria date scale, citrus blackfly, citrus
canker, Mediterranean fruitfly. Hall scale, and hoja blanca
of rice. The outlook is good for eradication of others —
such as the khapra beetle, witchweed, and golden nema-
tode. Federal-State efforts have checked spread of
the pink bollworm, Mexican fruitfly, gypsy moth, white-
fringed beetle, and Japanese beetle, thus preventing much
damage by these insects.

^ hile the use of chemicals against crop, animal, house-
hold, and human pests grew steadily, the public had no
Federal protection against fraudulent, ineffective, and un-
safe insecticides and fungicides — until the Department-
sponsored Insecticide Act of 1910 became law. Such
protection was broadened in 1947, 1959, and 1962 as new
chemicals came into use.

The Federal Insecticide, Fungicide, and Rodenticide
Act now requires registration, testing, and proper labeling
of more than 50.000 pest-control products shipped inter-
state for household, institutional, structural, and agricul-
tural uses.^V

5

More Traction and Efficiency from

TREAD

NEW
TIRE

Researchers believe a
more stable casing,
flattened tread base, narrow
rim width all contributed to
better overall performance
than from conventional tire

Flattened treadbase (dashes) of the
radial-ply tire distributes weight more
evenly than conventional rounded base.

Fabric cords in the
conventional tire
{top) are in diagonal
layers. But cords
in radial-ply tire
(bottom) are in
parallel layers.
Experimental tire
performed best.

■ An experimental tractor tire — so
smooth it resembles an inner tube —
outpulled a conventional tractor tire
by 40 percent under average condi-
tions in tests conducted at USDA's
National Tillage Machinery Lab-
oratory, Auburn, Ala.

The smooth tire was 14 percent
more efficient in converting axle
power into drawbar power.

The absence of lugs and differences
in internal construction contributed
to the tire's improved performance,
researchers believe.

Cords in the experimental tire cas-
ing are parallel across the tire (radial-
ply construction), rather than in
alternating diagonal layers as in con-
ventional casings. The tread base
of the tire is flatter than the round,
nearly circular tread base of a con-
ventional tire, and the rim width is
narrow (3^ inches) . Rim widths of
conventional tires range between 8
and 15 inches.

ARS agricultural engineers G. E.
Vanden Berg and I. F. Reed do not

6

know why these factors boosted trac-
tion, but they have some ideas. Thev
think that because the radial-ply tire
casing is more stable than a con-
ventional casing, there is more uni-
form contact with the soil. They also
believe a flattened tread base and
narrow rim width produce a tire that
distributes weight more evenly over
the soil than the base and rim width
of a conventional tire.

In one test on firm soil, a tire with
radial-ply, narrow rim, flattened tread
base, and lugs performed 27 percent
better than a standard tractor tire of
the same size. When a similar tire
was made smooth by buffing off the
lugs, its performance increased 41
percent over the standard tire with
lugs.

All tests were made in bins of four
soil types and on concrete. Only trac-
tion was evaluated, not wear or cost.

Lugs are needed on slick surfaces

According to the engineers, lugs
are essential for pulling on slick sur-
faces such as heavy grass, straw
mulch, or mud. But lugs as big as
those on conventional tires may not
be necessary for general farm use.

If similar findings are made in
additional research, Vanden Berg
and Reed believe the tractor tire of
the future will feature radial-ply con-
struction, flattened tread base, narrow
rims, and modified lugs for optimum
traction in both routine and heavy
pulling.^

Bonus
from
Chemical
Sterilants

• In studying means of producing sterility in insects, LSDA entomol-
ogists are finding that chemical sterilants may offer an unexpected
bonus — male houseflies treated with a chemical sterilant are unusually
vigorous and competitive in mating with females.

Maintenance of vigor and competitiveness of sterilized males is es-
sential for maximum results in insect control by sterilization, because
wild females that mate with sterile males lay eggs that do not hatch.
Thus, the more successfully sterilized males compete with wild males
in mating, the more effective is the sterilization method.

In tests at Orlando, Fla., the phemosrerjjar.t gphnlntn rrrtiltH in ex-
ceptional competitiveness of treated males.

Scientists had noted in earlier work that gamma radiation — the other
method of producing insect sterility — tends to injure and weaken insects.
Insects injured by irradiation are neither as long-lived nor as vigorous
and competitive as normal insects.

The entomologists determined competitiveness of chemosterilized
males — and thereby effectiveness of the treatment — by caging untreated
females at various ratios with sterile and normal males and recording
the hatch of the eggs. Theoretically, if the treated and untreated males
were equally competitive, a ratio of ten sterile males to one untreated
male and one untreated female (10:1:1) should result in 91 percent
reduction in egg hatch.

Results with apholate actually exceeded theoretical expectations. At
the ratio of 10:1:1, and at four other ratios down to 1:1:1, reduction
of hatch was always more than expected. One hatch reduction was 25
percent more than the theoretical expectation.

ARS entomologists G. C. LaBrecque, D. W. Meifert. and C. N. Smith
conducted the research in cooperation with the Department of Defense,
through the Armed Forces Pest Control Board. To sterilize the flies
chemically, the scientists incorporated 1 percent apholate in the food
of male flies for 3 days after emergence as adults. They also irradiated
some flies by exposing the pupae to 2.500 roentgens of gamma radiation.
The irradiated male flies were not as competitive as normal males, since
the reduction in egg hatch was less than the theoretical expectation.

The tests are being conducted to develop chemosterilant treatments,
using the housefly as a test insect. Objective of the research is to
obtain basic information about chemosterilants.

Much additional research will be needed before practical control of
insects can be achieved by chemosterilant applications.^

w a I

controlled

by
Insects ?

A flea beetle, a stem borer,
and a species of thrips seemed
most promising in first tests

■ South American insects that feed on alligatorweed
may aid in controlling this aquatic plant that often clogs
lakes, irrigation ditches, rivers, and ponds in the South-
eastern U.S.

ARS entomologist G. B. Vogt found the insects in
1960 and 1961, while searching for insect enemies of
alligatorweed in Argentina, Paraguay, and Brazil. (Vogt
was aided by scientists of South American governmental
organizations, museums, and universities.) About 2
years' work will probably be required to determine
whether any of the insects can be safely brought to the U.S.

Alligatorweed and water-hyacinth (Agr. Res., Febru-
ary 1962, p. 15) are the worst aquatic weeds in the
Southeast. These weeds interfere with agriculture, fish-

A saw-boat chops alligatorweed
and water-hyacinth choking a
southern U.S. waterway. This
sometimes spreads aquatic weeds.

eries. recreation, movement of traffic on navigable water-
wars, and hydroelectric power production. The weeds
also can endanger public health by creating mosquito-
breeding places.

Insects that eat alligatorweed help to control it in South
America. But in the U.S.. where the weed gained a foot-
hold about a century ago. the plant has no important
natural enemies.

Three of the insects — a flea beetle, a stem borer, and a
species of thrips — are most promising for suppressing
alligatorweed in this country. In all. \ ogt collected more
than 300 specimens of alligatorweed and closely related
plants and 40 to 50 kinds of insects that feed on them.

Entomologist will determine if insects can be brought to U.S.

But can these insects be safely and successfully intro-
duced into this country? ARS entomologist D. M. Mad-
dox will conduct intensive tests in Argentina to answer
the question. His laboratory is being set up in connec-
tion with the Argentina Experiment Station near Buenos
Aires. The U.S. Army Corps of Engineers, which is
responsible for maintaining navigable waterways in the
U.S.. will help to finance this research.

He will first concentrate his research on the flea beetle,
because it is most promising of the insects. He will make
feeding tests on manv L.S. crops and plants to be sure
the flea beetle attacks none of value. Buckwheat and
rhubarb are among the cultivated plants most closely
related to alligatorweed. In Vogt's preliminary tests, flea
beetles starved to death on buckwheat and rhubarb.

Two flea beetle parasites — a fungus and a small fly —
reduce beetle populations in South America. Maddox
plans to isolate the parasites from beetle colonies that
may be introduced into the L.S.

He may also have to adjust the flea beetle's life cycle to
U.S. seasons, which are opposite those in South America.

Maddox may need to explore farther into northern
South America to obtain more tropical insects for the
warm Gulf region and Florida.^

Flea beetles starved when scientist in Argentina
confined them to buckwheat (plastic bags) , but
they thrived on alligatorweed (rear).

Stem borer that damaged this alligator-

weed in South America might do the same in U.S.

9

IRONING
BOARD

SEWING
MACHINE

FLOOR AREA

U-shape center was
most easily used
by homemakers who
tested the unit.

CHEST

SEWING
MACHINE

WW
FLOOR AREA

IRONING
BOARD

L J

SEWING

CHEST

MACHINE

6X9*

FLOOR AREA

IRONING

BOARD

Parallel-wall unit
also fits well in
hall. All centers
take less space if
closet is used in
place of chest.

mm

FLOOR AREA

CHEST

IRONING
BOARD

One-wall unit is best
suited for being set
up in a hallway.

Cabinet and machine are
at right angles for
reach in l-shape.

CONVENIENT
HOME
SEWING
CENTERS

Use of these areas, set
up for efficiency, can aid
in saving time and energy,
and in avoiding strain

JEWING has been reported as a
^ household activity by three-
fourths of the rural homemakers in
regional housing surveys by State
experiment station and USD A re-
searchers.

In the South, some families re-
ported making as many as 60 gar-
ments a year. The latest nationwide
USD A survey shows that 40 percent
of all women make clothes for them-
selves and their families. Nearly 70
percent use a sewing machine to make
or mend clothes or household articles.

The surveys also show that home
sewing is done in many parts of the
house. Typically, a homemaker cuts
out a garment on the dining table,
presses on an ironing board in the
kitchen or laundry, and sews in a bed-
room. Work often must be done at
an uncomfortable height or angle or
in poor light.

10

■ Space for sewing, probably the
most disorganized of household jobs,
receives scant attention from archi-
tects and home builders. Yet several
USDA surveys show the need in most
homes for a place planned especially
for sewing.

A compact sewing center is needed
particularly in today's small house.
Now there are four such centers — U-
shape, L-shape, or with parallel-wall
or one-wall arrangements. These
centers were designed and tested at
the Georgia Agricultural Experiment
Station in the latest of three regional
studies with ARS.

Plans for the centers are based on
surveys of what homemakers use in
sewing, on measurements of space
needed for different sewing jobs, and
on tests of various working heights
and arrangements for storage of sup-
plies. Aim of the research is to help
homemakers save time and energy
and avoid strain when sewing.

In each center, equipment and sup-
plies for usual sewing are arranged
at comfortable working heights and
within easy reach of a seated person.

Least space needed for U-shape center

Of the four designs, the U-shape
center requires the least floor space
and proved most convenient when
tried by homemakers cooperating in
the studies. Minimum floor space
used for this center was 6^/2 by 7 feet.
But the L-shape arrangement (mini-
mum 4% by 10^ feet) may fit the
corner of a room better. The parallel-
wall (6 by 9 feet) center or the one-
wall (4^2 by 12 feet) center are best
for a hallway.

Any of these arrangements can
take up less floor space if the center
adjoins a closet that can be used in-
stead of a chest for storing supplies.

The U-shape center groups ironing
board, sewing machine, and supply
chest on three sides of a sewing chair.
A movable chair on casters enables

the homemaker to reach sewing sup-
plies and even do some pressing with-
out standing.

The studies show that homemakers
need at least 2 feet of space in front
of the ironing board, sewing machine,
and supply chest for comfortable
work. They need 2 feet of working
space on all sides of the cutting sur-
face for greatest convenience in
cutting out garments.

Most of the homemakers found
that the most convenient height for
cutting out garments was 36 inches

from the floor. Space needed for this
job was 3 by 4 to 6 feet.

Sewing centers designed are de-
scribed and illustrated in detail in
"Home Sewing Areas," an 8-page
leaflet that is free on request from the
School of Home Economics, Uni-
versity of Georgia, Athens, Ga. The
drawings are easy for a homemaker
to use in setting up her own sewing
center. The leaflet may be useful to
anyone who is planning a house
for convenience, comfort, and effi-
ciency.^

Extra- Attractive Easter Lilies

■ Many Easter lilies grown for the 1962 market will have ex-
ceptionally attractive flowers and foliage, because the bulbs from
which they grew were treated with a systemic insecticide — phorate
or Di-Syston.

While evaluating these two systemics for insect control, ARS
entomologist C. F. Doucette discovered that they also stimulate
growth. (A systemic insecticide is absorbed by plants and then
poisons certain insects that feed on them.) Doucette cooperated
with the Oregon Agricultural Experiment Station and commercial
lily bulb growers near Brookings, Oreg.

In the tests, granules of phorate or Di-Syston were applied to
bulbs planted in the field in the fall of 1958. The bulbs were
harvested a year later, and some were forced (stimulated artifici-
ally) in commercial greenhouses to produce plants for the 1960
market.

Doucette noted that plants grown from the treated bulbs had
more flowers, more attractive foliage, and more highly developed
root systems than could be attributed to control of pests known
to be affected by the systemics. Doucette concluded that the system-
ics controlled some unknown pests or brought about direct stimu-
lation of plant development.

Phorate and Di-Syston were subsequently registered by USDA
for commercial growers to use as insecticides. Some plants on the
1961 market were forced from treated bulbs. Use of the chemicals
was widespread for the first time on bulbs planted in 1960 to
produce plants this year.

Phorate or Di-Syston is applied to the bulbs after they are set in
the field, but before they are covered with soil. These insecticides
are toxic and should be used only by commercial growers who
are familiar with handling such chemicals.^

11

Small-Grain Pastures

■ Fatten steers on small-grain pastures? Georgia-USD A
researchers have studied this practice for more than 10
years and say it pays.

They found that small-grain pastures can be utilized
best by combining grazing and drylot feeding. This re-
sulted in lower feed costs than did feedlot-only fattening.
Animals fattened on pastures and in the feedlot gained
as fast or faster, and their finish grades equalled those of
animals fattened only in the feedlot.

In one of the most successful combinations of grazing
and drylot feeding, yearling steers were feedlot-fattened
76 days, then switched to oat pasture for 71 days. Aver-
age daily gain was 2.4 pounds, compared with 2.1 pounds
of gain for steers kept in the feedlot the whole time.
Estimated feed costs per 100 pounds of gain were $20.25
for the steers fattened and grazed, and $24.00 for those
kept in the feedlot. Both groups' slaughter grades
averaged good.

Feedlot rations consisted of about 70 percent ground
snapped corn, 10 percent cottonseed meal, and 20 percent
coastal bermudagrass hay. Steers grazing oats were each
given about 10 pounds of ground snapped corn daily.

Switching from pasture to feedlot also worked well.
In one trial, two groups of steers were started on a main-
tenance feeding program for 76 days, to allow time for
the pastures to get in grazing condition. The animals
received coastal bermudagrass hay during this period and
later when they were put on pasture. One group grazed
oat pasture 112 days, then was in the feedlot 35 days.
The other was in rye pasture 98 days, then spent 49 days
in the feedlot.

Steers in each group averaged about 2.4 pounds of daily

gain and graded good. Feed costs were about $18.50
per 100 pounds of gain for steers that grazed oats and
$22.00 for those that grazed rye.

The oats made better grazing than rye in this experi-
ment. But the scientists suggest an oat-rye crop rotation
system instead of continuous oat plantings. Rotation
planting will reduce chances of plant diseases ruining
the oats.

In these feedlot-and-grazing experiments, the cattle
utilized the complete growth of forage, so that no grain
could be harvested.

The study was conducted by Georgia animal husband-
men W. C. McCormick and D. W. Beardsley, and ARS-
Georgia animal husbandman B. L. Southwell at the
Georgia Coastal Plain Experiment Station, Tifton.

Results of these experiments confirm those of earlier
studies, which also showed that:

• Animals fattened only on grain pasture make less
daily gain and produce lower-grade carcasses than ani-
mals fattened in feedlots. Feeding costs are lower, how-
ever, for steers on pasture.

• Oats grazed for a limited time can provide a sub-
stantial amount of grain for harvest. Steers grazed about
70 days in each of 3 years in a test. The steers were re-
moved ( about the first of March) before the oats headed.
Average annual grain yield was 33 bushels an acre — in-
cluding a low 10-bushel yield the third year, due to an
oat disease.

The scientists say oats planted only for grazing should
be seeded about twice as heavily and fertilized more
liberally than oats planted for grain. Thick planting and
limited grazing, though, may result in good grain yields.^

PARASITES COMPETE OR COOPERATE

■ Some internal parasites of live-
stock apparently compete with each
other for survival, in addition to feed-
ing on their hosts, while other species
live together peacefully.

A recent USDA study of what hap-
pens to populations of three different
species of stomach worms in lambs

was designed to provide more infor-
mation about this compete-or-co-
operate phenomenon. Scientists are
conducting such research so they can
more accurately interpret results of
livestock parasite investigations.

Usually, experiments are designed
to show what one kind of parasite will

do to an animal. These studies are
valuable — they show how a parasite
species reacts to drug treatment, for
instance. But results can be mislead-
ing. An animal may be naturally in-
fested with several species of parasites
at the same time, and may not respond
as expected to medication.

12

In the recent study, larvae of each
species were force-fed to lambs. Some
lambs received larvae of only one
species, some got larvae of two species,
and some larvae of all three species.
About 3 months later, worms recov-
ered from each lamb's stomach were
counted and compared with the origi-
nal number of larvae fed each animal.

If all three species were in a lamb's
stomach, the population of one species,
the large stomach worm I Haemonchus
contortus I . was drastically reduced.
The population of another, the me-
dium stomach worm ( Ostertagia cir-
cumcincta I , was moderately reduced.
But the third species, the stomach hair-
worm I Trichostrongylus axei\. per-

sisted as well or better with the others
than when alone.

Large worm again was weak competitor

In the two-worm combinations, the
large worm was again the weak com-
petitor— based on comparisons of
larvae fed and worms recovered. If
large and medium worms were to-
gether, populations of both were
smaller than when either was alone.
Large worms were almost eliminated
when tried with stomach hairworms,
which did better in this combination
than by themselves. Hairworms also
thrived with medium stomach worms,
Avhich fared about as well alone or in
combination.

The study was conducted by ARS
parasitologists J. H. Turner, G. I. Wil-
son, and K. C. Kates. They worked
at USDA"s Parasitological Labora-
tory, Beltsville, Md.

Earlier experiments by Kates and
Turner showed that other species may
not compete with each other in sheep.
Populations of the large stomach
worm and the thread-neck worm
( Nematodirus spathiger) were greater
than when either species alone in-
fested the animals.

The scientists also demonstrated
that the same effects occurred when
intestinal hairworms {Trichostrongy-
lus colubrijormis) and thread-neck
worms infested sheep.^-

PLANTING TO BOOST PLANTAIN PRODUCTION

■ USDA research has opened the way for needed ex-
pansion of plantain production on the steep mountain
slopes of Puerto Rico and similar tropical areas.

Researchers demonstrated that yield of plantains ( cook-
ing bananas) can be almost doubled by growing 800
instead of the customary 500 trees per acre. The yield
from 800 trees per acre was 9.5 tons of fruit, compared
with 5.5 tons from 500 trees.

Increased production made possible by the higher plant-
ing rate could help densely populated Puerto Rico meet
its food needs. A USDA survey in 1953 showed that
Puerto Rico could use four times as many plantains as
were being produced.

ARS soil scientists Jose Vicente-Chandler and Jacinto
Figarella found that plants produced as well at the 800-
plant rate as at the 500-plant rate. Yield per tree, bunch
size, fruit size, and percent of trees bearing were not
significantly affected by the closer spacing.

The research, in cooperation with the University of
Puerto Rico Agricultural Experiment Station, also showed
that complete land preparation and clean cultivation are
not necessarv for maximum plantain yields.

In their experiments, Vicente-Chandler and Figarella
planted plantain corms in holes dug in undisturbed grass
sod. They had killed top growth of the short grass with
a heavy application of pentachlorophenol and oil, leaving
an erosion-preventing mulch. The scientists cultivated
to eliminate weeds in plantain rows but allowed volun-
teer grasses to grow between rows. All plots were heavily

fertilized and protected against insects, diseases, and
nematodes.

Yields from sod plots planted at the conventional rate
were equal to those from cultivated plots planted at the
same rate. This indicated that competition from between-
row grass did not reduce production.

Crop production on the mountain slopes of Puerto Rico
has been restricted by erosion and the difficulty of using
machinery. Intense tropical rains erode plowed soil on
the slopes. Planting in sod lessens erosion, and equip-
ment can be operated more easily.

The scientists estimate that plantains can be grown in
undisturbed sod on 400,000 acres of steep mountains in
Puerto Rico that are not now used to produce food crops.
And planting 800 corms per acre would give maximum
yield on this soil, as well as on other land currently
in plantains.^

Soil wasn't cultivated in plots of 800 trees per
acre. Contact herbicide reduced grass growth.

Distinctive
Flavors
From

FAT

Hornstein uses gas
chromatography to
identify chemical
components of
meat aromas.

Carbonyls — compounds in fatty parts of beef,
lamb, and pork — seem responsible for the way
these meats taste after they are cooked

■ It's the fatty portions of beef, lamb, and pork that give
these meats their distinctive flavors. The lean portions
all taste about the same.

These are conclusions of USDA chemists from basic
research on meat flavors. Recent work on lamb seems
to narrow down the substances responsible for its char-
acteristic flavor to a class of compounds in the fat known
as carbonyls.

The aroma of roast lean beef, pork, or lamb can be
produced by soaking each meat in cold water, then freeze-
drying the extract to a powder and heating it. But if no
fat is present, the kind of meat producing the aroma can-
not be identified, either by smell or by trapping the aromas
given off and analyzing them for their chemical constit-

uents. When the fats of these meats are similarly heated,
on the other hand, they give off distinctive odors. The
chemical constituents of these aromas, while roughly
similar, vary widely in proportions and amounts.

Chemists I. Hornstein and P. F. Crowe of the ARS
Eastern utilization division, Beltsville, Md., are carrying
out these experiments. They explain that isolating the
flavor source of a food like meat, whose full flavor is
developed only by cooking, is a two-fold operation. First,
the chemists analyze the aromas given off by heated meat
to determine the chemical components. Then they look
for the aroma precursors — compounds in the raw meat
that are converted by heating to the compounds responsi-
ble for the cooked flavor.

The chemists were especially interested in the strong
mutton aroma obtained when they heated rendered lamb
fat. Realizing the potentialities for increasing the con-
sumer acceptance of lamb through modification of this
flavor, the scientists began a search for its origin. Their
suspicion was that the mutton flavor might be coming from
some compounds broadly classified by chemists as
carbonyls.

So they placed mutton aroma in contact with a chem-
ical (2,4-dinitrophenylhydrazine)" that reacts with
carbonyls specifically. This removed the carbonyls and
considerably reduced the mutton aroma. The experiment
showed that carbonyls are at least partially responsible
for the flavor.

Then Hornstein and Crowe analyzed the raw lamb fat to
see if carbonyls present were the precursors of cooked
flavor compounds. Fat was dissolved in hexane and
treated with the same carbonyl-reacting chemical used
before. About 97 percent of the fat was recovered
carbonyl-free. Heating it produced no mutton aroma.

All carbonyls in the fat, converted to another form by
the reactant, were present in the remaining 3 percent.
This fraction was analyzed first for total carbonyls, then
for individual carbonyls. The chemists have not yet
identified all carbonyls the first test indicated were present.
Carbonyls identified were not of the types that would
account for lamb flavor.

Thus, the specific chemical components of lamb re-
sponsible for its mutton flavor have so far escaped posi-
tive identification. The researchers believe, however,
that the flavor components are among the unidentified
carbonyls. Hornstein and Crowe are working to precisely
identify these carbonyls.^-

14

AG RISE ARCH NOTES

Wilder medal awarded to ARS unit

The Wilder Silver Medal for "lead-
ership in developing virus-free straw-
berries" has been awarded to the
small fruit investigations unit of ARS.
This award is given by the American
Pomological Society.

The highest award of the society,
the Wilder medal was established in
1873 and is given annually in recog-
nition of outstanding work in horti-
culture.

Until this accomplishment by the
USDA scientists, viruses plagued
strawberry growers in North Amer-
ica. Growers could not obtain any
virus-free plants of certain varieties.

The researchers also developed
methods of keeping stock virus-free
while it is increased. As a result,
many nurseries are now able to supply
virus-free strawberry plants. Virus-
free plants produce more and better
berries and have a longer productive
life than infected plants.

Most of the important strawberry-
producing States have set up virus-
free certification and improvement
programs.

Turkey study results in saving

A saving of $200,000 a year by the
turkey industry is the net result of
a short-term study conducted by
USDA investigators.

They found that some turkeys
apparently infected by visceral lym-
phomatosis— a form of avian leuko-
sis— but actually infected by black-
head disease, were being condemned
during processing.

Federal inspectors at processing
plants must condemn birds with leu-
kosis. But if birds have any of
several other diseases, including

blackhead, only the infected parts
must be discarded.

An unusually large number of tur-
keys being condemned due to leu-
kosis in some areas alerted AMS
poultry pathologists G. S. McKee and
F. C. Love. They checked some
processing plants and found that
birds having peculiarly nodulated
spleens were being condemned. This
is a leukosis symptom, but can be
mistaken for blackhead.

McKee and Love were aided by
ARS research zoologist A. M. Lucas

and biologist E. M. Denington. They
discovered that nodulated spleens — if
there is no evidence of leukosis in
other parts of the turkey's body —
result from reactions to blackhead,
not to visceral lymphomatosis.

The scientists say blackhead can
usually be recognized when livers
have distinctive lesions. But these
might be absent if diseased birds are
given blackhead-combating drugs.
So the only evidence of disease may-
be a nodulated spleen that appears
leukotic. When spleens are leukotic,
other organs will also indicate the
presence of leukosis.

McKee and Love are stationed in
Washington, D.C. Lucas and Den-
ington work at East Lansing, Mich.

Inbred dent corn lines released

Two new inbred lines of dent corn,
Mo 12 and Mo 13, have been released
by USDA and the Missouri Agricul-
tural Experiment Station.

Plant breeders use inbred lines as
parent stock in developing hybrids.

The lines are selected for the desirable
characteristics they impart to the
hybrids.

In single- and three-way crosses
with other inbreds, Mo 12 and Mo 13
have produced offspring with supe-
rior yield performance. Mo 12, has
very dark green leaves and pale yel-
low kernels. It shows good resistance
to leaf-firing during drought. Mo 13
has good resistance to lodging, and
better than average earworm resist-
ance. Both inbred lines are late-
maturing strains adapted to growing
conditions in Missouri and other
States in similar latitudes.

These inbreds were developed by
ARS agronomist M. S. Zuber at the
Missouri station.

Hand-pollinated seed of Mo 12 and
Mo 13 is available from the Foun-
dation Seed Stocks Project, 108 Wa-
ters Hall, Columbia, Mo.

Gains from earlier peach thinning

USDA studies have confirmed the
value of thinning fruits of early ripen-
ing peach varieties soon after bloom
to increase fruit size. The research
also shows that earlier thinning leads
to earlier ripening of peaches, a
heavier bloom, and a bigger yield the
next year.

Most previous investigations on
affect of time of peach thinning were
done with Elberta, a late-ripening
variety, and effects other than in-
creased fruit size were inconsistent.
To get more information on response
of early ripening varieties to time of
removing immature fruits, ARS horti-
culturist A. L. Havis conducted tests
in a Redhaven peach orchard at Belts-
ville, Md.

Earliest thinning was done at
bloom. Later thinnings, at 2-week

15

UNITED STATES GOVERNMENT PRINTING OFFICE

DIVISION OF PUBLIC DOCUMENTS, WASHINGTON 25. D.C.
OFFICIAL BUSINESS

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AG RISE ARCH NOTES

intervals, were made until about 10
days before the first harvesting date.

Peaches on trees thinned earliest
ripened earliest. Fruit size and yield
were increased substantially in trees
thinned up to 8 weeks after bloom, but
were greatest on those thinned ear-
liest. These effects are more evident
with Redhaven than with late-ripen-
ing peach varieties.

Trees thinned within a month after
bloom had good bloom the next sea-
son, but those thinned just before

harvest had only 40 to 50 blossoms
per tree the next year.

Time of thinning does not seem to
affect fruit flavor, texture, firmness,
or skin color.

USDA introduction is good parent

A sweetpotato brought to this coun-
try by USDA in 1946 is the source of
disease resistance in Nugget, a new
variety developed by scientists of the
North Carolina Agricultural Experi-
ment Station.

Nugget may replace disease-
susceptible Porto Rico, the major
commercial variety of sweetpotatoes
grown in the U.S. The new variety
produces good yields and resists in/
ternal cork and wilt. Nugget's higli-
quality tubers have orange flesh. \

The sweetpotato used to develop

Nugget was found on Tinian Island,
one of the Marianas in the Pacific.
After 2 years of testing in this coun-
try, this introduction showed great
promise as a source of resistance to
stem rot (wilt) disease. It was re-
leased to plant breeders in 1948 as a
source of disease resistance.

New pioneering laboratory in Ohio

Research in a new USDA lab-
oratory at Wooster, Ohio, is aimed
at developing basic knowledge that
may lead to improved methods of ap-
plying pesticides and fertilizers, or
help to reduce air pollution.

At this Pioneering Research Lab-
oratory on the Physics of Fine Parti-
cles, ARS agricultural engineer R. D.
Brazee is studying the formation and
physical behavior of finely divided
liquid and solid particles.

He hopes to develop mathematical
descriptions of fine particles, and to
devise equipment for measuring their
movement as aerosols (droplets of
liquid suspended in air) . Brazee will
also measure the influence on particles
exerted by forces such as temperature
and wind, and study factors affecting
these forces.

The pioneering laboratory is housed
at the Ohio Agricultural Experiment
Station^-.-. . —

Award won by USDA chemist

Allene R. Jeanes, a chemist of the
ARS Northern utilization division/
Peoria, 111., is one of six Government

career women and the first in USDA
to receive the Federal Woman's
Award.

The award cites "her pioneering
chemical research on the starches and
sugars obtained from cereal grain."

The Federal Woman's Award,
given for the first time last year, is
the only honor exclusively for career
women in the Federal Government.

Dr. Jeanes won the award for her
sustained contributions to the chem-
istry of microbial polysaccharides, in-
cluding a prominent part in develop-
ing dextran, a product of sugar

fermentation used as a blood plasma
extender. This material, of particular
value to the Armed Forces and civil
defense when large quantities of
plasma are needed, alleviates shock by
stopping excessive movement of water
from blood to body tissues.

For her work on dextran, Dr.
Jeanes also has won USDA's Dis-
tinguished Service Award and the
Garvan Medal of the American Chem-
ical Society for distinguished service
to chemistry by a woman scientist,

16

U.S. GOVERNMENT PRINTING OFFICE: 1962